Claude M. Nagamine

Assistant Professor of Comparative Medicine at the Stanford University Medical Center

Bio

Bio

Claude M. Nagamine, DVM, PhD Assistant Professor received his D.V.M. from the University of Tennessee in 2004 and completed his residency training in Laboratory Animal Medicine at the Massachusetts Institute of Technology in 2007. He joined the Department of Comparative Medicine at Stanford in 2008. Prior to entering veterinary school, Dr. Nagamine obtained a Ph.D. in Ecology from the University of California, Davis (1979), obtained postdoctoral training in endocrinology, developmental genetics, immunology, and molecular biology of the mouse at the Memorial Sloan-Kettering Cancer Center (NYC), Institut Pasteur (France), and the Howard Hughes Medical Institute at the University of California, San Francisco and was an Assistant Professor of Cell Biology at the Vanderbilt University School of Medicine. His research focuses on using mouse models to study murine and human infectious diseases. These colloborative studies include dengue virus, zika virus, adeno-associated virus, coxsackie virus, enterohepatic helicobacters, campylobacters, and anaplasma.

Publications

All Publications

Abstract

Neonatal mice (that is, pups younger than 6 d) must be exposed to CO2 for as long as 50 min to achieve euthanasia. Alternatively, other inhalant anesthetic agents have been used to euthanize laboratory rodent species. We investigated the efficacy of isoflurane at saturated vapor pressure to euthanize neonatal mice. Neonatal mice (n = 76; age, 1 or 2 d) were exposed to isoflurane in a sealed, quart-size (0.95-L) plastic bag at room temperature. Righting and withdrawal reflexes were absent in less than 2 min. After 30 min of exposure to isoflurane, pups were removed and monitored for recovery. All pups were cyanotic and showed no detectable signs of life when they were removed from the bag. However, after 30 to 120 min after removal from the bag, 24% of isoflurane-overexposed pups began gasping and then resumed normal respiration and regained a normal pink coloration. These results demonstrate that isoflurane overexposure at saturated vapor pressure for 30 min is insufficient to euthanize neonatal mice and that isoflurane overexposure must be followed by a secondary means of euthanasia.

Abstract

Adeno-associated virus (AAV) vectors are currently the leading candidates for virus-based gene therapies because of their broad tissue tropism, non-pathogenic nature and low immunogenicity. They have been successfully used in clinical trials to treat hereditary diseases such as haemophilia B (ref. 2), and have been approved for treatment of lipoprotein lipase deficiency in Europe. Considerable efforts have been made to engineer AAV variants with novel and biomedically valuable cell tropisms to allow efficacious systemic administration, yet basic aspects of AAV cellular entry are still poorly understood. In particular, the protein receptor(s) required for AAV entry after cell attachment remains unknown. Here we use an unbiased genetic screen to identify proteins essential for AAV serotype 2 (AAV2) infection in a haploid human cell line. The most significantly enriched gene of the screen encodes a previously uncharacterized type I transmembrane protein, KIAA0319L (denoted hereafter as AAV receptor (AAVR)). We characterize AAVR as a protein capable of rapid endocytosis from the plasma membrane and trafficking to the trans-Golgi network. We show that AAVR directly binds to AAV2 particles, and that anti-AAVR antibodies efficiently block AAV2 infection. Moreover, genetic ablation of AAVR renders a wide range of mammalian cell types highly resistant to AAV2 infection. Notably, AAVR serves as a critical host factor for all tested AAV serotypes. The importance of AAVR for in vivo gene delivery is further highlighted by the robust resistance of Aavr(-/-) (also known as Au040320(-/-) and Kiaa0319l(-/-)) mice to AAV infection. Collectively, our data indicate that AAVR is a universal receptor involved in AAV infection.

Abstract

We report the isolation of a novel helicobacter isolated from the caecum of the Siberian hamster (Phodopus sungorus). Sequence analysis showed 97% sequence similarity to Helicobacter ganmani. In addition, we report the co-infection of these Siberian hamsters with a Campylobacter sp. and a second Helicobacter sp. with 99% sequence similarity to Helicobacter sp. flexispira taxon 8 (Helicobacter bilis), a species isolated previously from patients with bacteraemia. Gross necropsy and histopathology did not reveal any overt pathological lesions of the liver and gastrointestinal tract that could be attributed to the Helicobacter or Campylobacter spp. infections. This is the first helicobacter to be identified in the Siberian hamster and the first report of co-infection of Helicobacter spp. and Campylobacter sp. in asymptomatic Siberian hamsters.

Abstract

PURPOSE: This research aimed to study the use of Cerenkov luminescence imaging (CLI) for non-Hodgkin's lymphoma (NHL) using (89)Zr-rituximab positron emission tomography (PET) tracer with a humanized transgenic mouse model that expresses human CD20 and the correlation of CLI with PET. PROCEDURES: Zr-rituximab (2.6 MBq) was tail vein-injected into transgenic mice that express the human CD20 on their B cells (huCD20TM). One group (n?=?3) received 2 mg/kg pre-dose (blocking) of cold rituximab 2 h prior to tracer; a second group (n?=?3) had no pre-dose (non-blocking). CLI was performed using a cooled charge-coupled device optical imager. We also performed PET imaging and ex vivo studies in order to confirm the in vivo CLI results. At each time point (4, 24, 48, 72, and 96 h), two groups of mice were imaged in vivo and ex vivo with CLI and PET, and at 96 h, organs were measured by gamma counter. RESULTS: huCD20 transgenic mice injected with (89)Zr-rituximab demonstrated a high-contrast CLI image compared to mice blocked with a cold dose. At various time points of 4-96 h post-radiotracer injection, the in vivo CLI signal intensity showed specific uptake in the spleen where B cells reside and, hence, the huCD20 biomarker is present at very high levels. The time-activity curve of dose decay-corrected CLI intensity and percent injected dose per gram of tissue of PET uptake in the spleen were increased over the time period (4-96 h). At 96 h, the (89)Zr-rituximab uptake ratio (non-blocking vs blocking) counted (mean?±?standard deviation) for the spleen was 1.5?±?0.6 for CLI and 1.9?±?0.3 for PET. Furthermore, spleen uptake measurements (non-blocking and blocking of all time points) of CLI vs PET showed good correlation (R (2)?=?0.85 and slope?=?0.576), which also confirmed the corresponding correlations parameter value (R (2)?=?0.834 and slope?=?0.47) obtained for ex vivo measurements. CONCLUSIONS: CLI and PET of huCD20 transgenic mice injected with (89)Zr-rituximab demonstrated that the tracer was able to target huCD20-expressing B cells. The in vivo and ex vivo tracer uptake corresponding to the CLI radiance intensity from the spleen is in good agreement with PET. In this report, we have validated the use of CLI with PET for NHL imaging in huCD20TM.

Abstract

Autophagy is an important component of the innate immune response, directly destroying many intracellular pathogens. However, some pathogens, including several RNA viruses, subvert the autophagy pathway, or components of the pathway, to facilitate their replication. In the present study, the effect of inhibiting autophagy on the growth of dengue virus was tested using a novel inhibitor, spautin-1 (specific and potent autophagy inhibitor 1). Inhibition of autophagy by spautin-1 generated heat-sensitive, noninfectious dengue virus particles, revealing a large effect of components of the autophagy pathway on viral maturation. A smaller effect on viral RNA accumulation was also observed. Conversely, stimulation of autophagy resulted in increased viral titers and pathogenicity in the mouse. We conclude that the presence of functional autophagy components facilitates viral RNA replication and, more importantly, is required for infectious dengue virus production. Pharmacological inhibition of host processes is an attractive antiviral strategy to avoid selection of treatment-resistant variants, and inhibitors of autophagy may prove to be valuable therapeutics against dengue virus infection and pathogenesis.

Abstract

After rederivation of a mouse parvovirus (MPV)-contaminated transgenic mouse strain, serology and PCR testing of the surrogate dam showed it to be infected with mouse parvovirus strain 1 (MPV-1). The rederived pups (n = 3) also were MPVpositive, according to serology. Despite MPV seropositivity, fecal PCR tests of the pups were negative, as were serologic results from direct-contact sentinels. Only one rederived pup survived, and this male was bred successfully. None of its mates or progeny seroconverted to MPV. At 14.5 mo of age, the rederived male mouse was euthanized; tissues were collected and submitted for MPV testing; both serologic tests and PCR analysis of mesenteric lymph nodes were MPV-negative. One explanation for the rederived pups' MPV seropostivity is passive transfer of maternal antibodies or a nonproductive MPV infection. This case illustrates that although routine serological testing of surrogate mothers and pups is appropriate, any positive results should be further investigated by using transmissibility testing (fecal PCR or contact sentinels or both) prior to repeat rederivation.

Abstract

Disposable individually ventilated cages have lids that restrict air exchange when the cage is not mechanically ventilated. This design feature may cause intracage CO2 to increase and O2 to decrease (hypercapnic and hypoxic conditions, respectively) when the electrical supply to the ventilated rack fails, the ventilated rack malfunctions, cages are docked in the rack incorrectly, or cages are removed from the ventilated rack for extended periods of time. We investigated how quickly hypercapnic and hypoxic conditions developed within disposable individually ventilated cages after removal from mechanical ventilation and compared the data with nondisposable static cages, disposable static cages, and unventilated nondisposable individually ventilated cages. When disposable individually ventilated cages with 5 adult mice per cage were removed from mechanical ventilation, CO2 concentrations increased from less than 1% at 0 h to approximately 5% at 3 h and O2 levels dropped from more than 20% at 0 h to 11.7% at 6 h. The breathing pattern of the mice showed a prominent abdominal component (hyperventilation). Changes were similar for 4 adult mice per cage, reaching at least 5% CO2 at 4 h and 13.0% O2 at 6 h. For 3 or 2 mice per cage, values were 4.6% CO2 and 14.7% O2 and 3.04% CO2 and 17.1% O2, respectively, at 6 h. These results document that within disposable individually ventilated cages, a hypercapnic and hypoxic microenvironment develops within hours in the absence of mechanical ventilation.